The present invention relates to downhole drilling assemblies, specifically downhole drilling assemblies for use in oil, gas, geothermal, and horizontal drilling. The ability to efficiently provide a power source downhole is desirable to electronically and mechanically power downhole instrumentation. The following patents attempt to solve the problem of generating electricity downhole.
U.S. Pat. No. 5,626,200 to Gilbert et al., which is herein incorporated by reference for all that it contains discloses a logging-while-drilling tool for use in a wellbore in which the tool includes an alternator for providing power to the electronics, and a turbine for driving the alternator. The turbine blades are driven by the well fluid introduced into the hollow drill string. The tool also includes a deflector to deflect a portion of the well fluid away from the turbine blades.
U.S. Pat. No. 5,839,508 to Tubel et al., which is herein incorporated by reference for all that it contains, discloses an electrical generating apparatus which connects to the production tubing. In a preferred embodiment, this apparatus includes a housing having a primary flow passageway in communication with the production tubing. The housing also includes a laterally displaced side passageway communicating with the primary flow passageway such that production fluid passes upwardly towards the surface through the primary and side passageways. A flow diverter may be positioned in the housing to divert a variable amount of the production fluid from the production tubing and into the side passageway. In accordance with an important feature of this invention, an electrical generator is located at least partially in or along the side passageway. The electrical generator generates electricity through the interaction of the flowing production fluid.
U.S. Pat. No. 7,624,821 to Hall et al., which is herein incorporated by reference for all it contains, discloses a downhole tool string component with a bore adapted to accommodate drilling mud having a central passage and at least one periphery passage. At least two movable segments are peripherally positioned around a bore wall adapted to constrict a diameter of the central passage and are adapted to divert drilling mud into the at least one periphery passage. At least one opening mechanism is adapted to move a portion of the at least two movable segments toward the bore wall. Debris in the drilling fluid may get lodged in the movable parts and hinges of this invention thereby impairing the normal function of the movable segments.